toooldforfandom is a user on octodon.social. You can follow them or interact with them if you have an account anywhere in the fediverse.
If you don't, you can sign up here.
An alternative, without changing how #mastodon works, would be for someone to crawl most instances, store the results and then provide a way to search tags or subscribe to tags. https://www.tootsearch.com tries but it doesn't work that well.
Of course, I have seen people deeply against any kind of multi-instance search so...
